/*
 * AutoCompleteTextField.java 6 aout 2011
 *
 * Sweet Home 3D, Copyright (c) 2011 Emmanuel PUYBARET / eTeks <info@eteks.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.eteks.sweethome3d.swing;

import java.text.Collator;
import java.util.Comparator;
import java.util.List;
import java.util.TreeSet;

import javax.swing.JTextField;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

/**
 * A text field that suggests to the user strings stored in auto completion strings in the user preferences.
 * Inspired from the code released in public domain by Samuel Sjoberg on his 
 * <a href="http://samuelsjoberg.com/archive/2009/10/autocompletion-in-swing">blog</a>.
 * @author Emmanuel Puybaret
 */
public class AutoCompleteTextField extends JTextField
{
	private List<String> autoCompletionStrings;
	private boolean directChange;
	
	public AutoCompleteTextField(String text, int preferredLength, List<String> autoCompletionStrings)
	{
		super(preferredLength);
		this.autoCompletionStrings = autoCompletionStrings;
		setDocument(new AutoCompleteDocument(text));
		this.directChange = true;
	}
	
	@Override
	public void setText(String t)
	{
		this.directChange = false;
		super.setText(t);
		this.directChange = true;
	}
	
	/**
	 * Document able to autocomplete.
	 */
	private class AutoCompleteDocument extends PlainDocument
	{
		
		public AutoCompleteDocument(String text)
		{
			try
			{
				replace(0, 0, text, null);
			}
			catch (BadLocationException ex)
			{
				throw new RuntimeException(ex);
			}
		}
		
		@Override
		public void insertString(int offset, String string, AttributeSet attr) throws BadLocationException
		{
			if (directChange && (string != null && string.length() > 0))
			{
				int length = getLength();
				if (offset == length || (offset == getSelectionStart() && length - 1 == getSelectionEnd()))
				{
					String textAtOffset = getText(0, offset);
					String completion = autoComplete(textAtOffset + string);
					if (completion != null)
					{
						int completionIndex = offset + string.length();
						super.remove(offset, length - offset);
						super.insertString(offset, string, attr);
						super.insertString(completionIndex, completion.substring(completionIndex), attr);
						select(completionIndex, getLength());
						return;
					}
				}
			}
			super.insertString(offset, string, attr);
		}
		
		private String autoComplete(String stringStart)
		{
			stringStart = stringStart.toLowerCase();
			// Keep suggestions in alphabetical order
			final Collator comparator = Collator.getInstance();
			comparator.setStrength(Collator.TERTIARY);
			TreeSet<String> matchingStrings = new TreeSet<String>(new Comparator<String>()
			{
				public int compare(String s1, String s2)
				{
					return comparator.compare(s1, s2);
				}
			});
			// Find matching strings
			for (String s : autoCompletionStrings)
			{
				if (s.toLowerCase().startsWith(stringStart))
				{
					matchingStrings.add(s);
				}
			}
			if (matchingStrings.size() > 0)
			{
				// Return the first found one
				return matchingStrings.first();
			}
			else
			{
				return null;
			}
		}
	}
}
